Malaysia's leader played down fears Monday that the ruling coalition's loss at a special parliamentary election signaled a drop in support in one of its most crucial political strongholds, the Associated Press reported.

The opposition narrowly wrested a legislature seat in Sarawak state on Borneo island, where Prime Minister Najib Razak's National Front ruling coalition has enjoyed decades of support among Borneo's main population of indigenous tribes.

The state is pivotal because opposition leader Anwar Ibrahim's three-party alliance needs to win more parliamentary seats there if it wants to achieve its aim of seizing federal power in general elections expected before 2013.

Najib said the government will study the reasons for its defeat in the Sibu constituency, but stressed that the opposition's razor-thin margin of victory was "not really a decisive result to say one way or the other."

"I believe our strength is still there," Najib told reporters. "Our traditional support has remained intact."

The opposition won the seat by a majority of 398 votes out of nearly 38,000 ballots cast Sunday. It had been held by a National Front incumbent since 2008 general elections, but he died of cancer last month.

Sibu has been under the National Front's control for many years, but two-thirds of its voters are minority ethnic Chinese, who have increasingly accused the ethnic Malay Muslim-dominated government of racial discrimination.

In the 2008 elections, the National Front lost more than one-third of the seats in Parliament to the opposition amid complaints of corruption and discrimination against minorities in economic policies. However, Sarawak and another Borneo state remained firmly on the Front's side, helping it to retain federal power.